Inclosed fuse



A. L. EUSTICE.

IINCLOSED FUSE.

APPLICATION FILED MAR. 7, 191a.

Patented June 13, 1922.

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UNITED STATES ALFRED L. EUSTICE, OF CHICAGO, ILLINOIS.

Incnosnn FUSE.

T 0 all to 710m it may concern Be it known that I, ALFRED L. EUsTron, acitizen of the United States, and resident of Chicago, in the county ofCook and State of Illinois, have invented certain new and usefulImprovements in Inclosed Fuses, of which the following is aspecification.

This invention relates to inclosed fuses.

One of the objects of the invention is to prevent any operativeassociation of the metal of the fusible element after the latter hasbeen melted.

Another object is to improve the means for confining a given portion ofa fusible member within an air space to obtain greater sensitiveness inthe melting of the fusible member.

Generally speaking, these and other objects are accomplished byproviding in a fuse, the combination of a closed casing, a fusibleelement mounted therein and electrically connected exteriorly ofthecasing, and separable members forming an air space around a portionof the fusible element to increase its sensitiveness and to prevent anyoperativeassociation of the metal of the fusible element after. thelatter is melted.

The invention is illustrated on the accompa nying sheet of drawings, inwhic'h--.

Figure 1 is a longitudinal sectional view of a fuse embodying myinvention;

Figure 2 is a transverse sectional view taken in the plane of line 22 ofFigure 1;

Figure 3 .is a longitudinal sectional view of the same fuse'taken ataidifferent angle from that shown in Figure 1; V

Figure f is a transverse sectional. view taken in the plane of line i 1of Figure 3.;

Figure 5 is a perspective view of one of the semispherical members forenclosing a portion of the fusible element; and,

Figure 6 is a perspective view of an insulating member interposedbetweentwo semispherical members.

The various novel features of my invention will be apparent from thefollowing description and drawings and will be particularly pointed outin the appended claims. i

Referring to the figures of the drawings, it will be noted that I haveprovided a fuse which includes a cylindrical casing 10, preferablyformed of insulating material, the ends of the casing being closed bymetallic electrical conducting caps, 11. Terminal straps 12, whichextend diametrically Specification of Letters Patent.

ment.

Patented June 13, 1922.

Application filed March 7, 1918. Serial No. 220,962.

through the casing 10, are electrically connected with the conductingcaps 11. Connecting the terminal straps 12 is a fusible element ormember 13, the ends of which may be secured to the terminal straps 12 inany suitable manner. In this particular instance the ends of the fusibleelement 13 are secured to the terminal straps 12 by screws 1 f.

As is customary in this type of fuse, the

casing 10 is filled with any suitable amount of non-conducting material15, preferably in a pulverulent or finely powdered state, such asasbestos, plaster-of-Paris or slaked lime,

adapted to dissipate the heat and provide minute paths or intersticesfor the escape of the vapor or gases arising or evolved upon the meltingof the fusible element.

It has been found that when the fusible element 1s packed in theinsulating material,

as .hereinabove described, it sometimes happens that after the fusibleelement has been melted there is still an operativeassociation of themetal of the fusible element, which permits passage of currenttherethrough,

and, as a matter of fact, the fusible element may .become so mixed withthe packingmaterlal as to cause the resistance of the fusible element tobe materially altered, there by defeating the very object of the safetyfuse.'

This undesirable feature is overcome by placing a protecting enclosurearound'a portion of the fusible element by providing a plurality of.semispherical members, 16, which fit over a portion of the fusibleeleslipped over the ends of the fusible element Each of thesemispherical members 1 3 before the latter has been secured to the rwith each other by acentrally arranged in sulating disk 18, alsoplOVIClBClWltll an aper- By means of the cooperative association of thesemispherical members 16, an air space 1S formed,,wh1ch 111 this case isaround the central partof the fusible element 13.

Tnthis manner. the heat which is generated by current passing throughthe fusible eleterminal straps 12., These semispherical members are heldout of electrical contact 'Q ough which the fusible element eX- tends.These separable semispherical me ment is retained in the air chamber 19,thereby making it possible to determine with a great degree of nicetythe load which will cause the melting of the fuse. The radiation alsounder these conditions is maintained constant, which greatly adds to thesensitiveness of the arrangement in question.

The semispherical members 16, preferably are of hardened metal toprevent substitution of the fusible element after it has been melted. Afurther advantage of such an arrangement is that it makes possible theprevention of the establishment of any electrical connection between theends of the closed casing after the fuse element has blown. The metalmembers are of such material as to prevent a foreign substance frombeing driven therethrough. Furthermore, the insulating disk interposedbe tween the separable members forming the hollow portion about thefusible member prevents the melted fusible member from permittingelectrical. connection after the same has blown. It would be ratherdifficult, if not impossible, to drive a nail through the member 16 tobridge the separate ends of the melted fusible member or to bridge theterminal straps 12. The members 16 also would act to deflect any objectcoming in contact therewith if it was attempted to drive that objectthrough said members.

It is apparent that there may be various modifications of the inventionherein particularly shown and described and it is my intention to coverall such modifications which do not involve a departure from the spiritand scope of the invention as defined by the following claims.

I claim:

1. In a fuse, the combination of a closed casing, a fusible elementmounted therein and electrically connected exteriorly thereof, andcomplementary semispherical mem bers forming an air space around aportion of the fusible element to increase the sensi tiveness of thelatter.

2. In a fuse. the combination of a. closed easing, a fusible elementmounted therein and electrically connected exteriorly there of, and anapertured hollow member through which the fusible element extends and bymeans of which an air space is formed around the fusible element toincrease the sensitiveness thereof, said hollow member being shaped topresent deflecting surfaces toward the ends of said casing.

3. In a fuse, the combination of a closed casing, a fusible elementmounted therein and electrically connected exteriorly thereof, aplurality of associated conducting members forming an air space around aportion of the fuse to increase the sensitiveness thereof, and aninsulating medium between said associated members to prevent currentpassing from one member to another.

4t. In a fuse, the combination of a closed casing, a fusible elementmounted therein and electrically connected exteriorly thereof, aplurality of associated conducting members forming an air space around.the fusible element to increase the sensitiveness thereof, and aninsulating member separating said members to prevent the passage ofcurrent therethrough, all of said members having apertures through whichthe fusible ele ment extends.

5. In a fuse, thecombination of a closed casing, a fusible elementmounted therein, and a hard deflecting shell within the casing enclosingan intermediate portion of said fusible element.

6. In a fuse, the combination of a closed casing, a fusible elementmounted therein, and deflecting means of relatively hard material withinsaid casing enclosing an intermediate portion of the fusible element.

7. In a fuse, the combination of a closed casing, a fusible elementmounted therein and electrically connected exteriorly thereof,complementary semispheri all members form ing an air space around aportion of the fusible element to increase the sensitiveness of thelatter. and an insulating" disk separating said semispherical members toprevent establishment of electrical connections therebetween by themetal of the fusible element after the same has melted.

S. In a fuse, the combination of a closed casing, a fusible elementmounted therein. and a hard deflecting shell within the wasing enclosingan intermediate portion of said fusible element, said shell beingprovided with an apertured diaphragm of non-conducting material.

In. a fuse, the combination of a closed casing. a fusible elementmounted therein. and a hard deflecting shell within the casing enclosingan intermediate portion of said fusible element. said shell beingdivii'led transversely of said fusible clement by an insulating member.I

10. In a fuse, the con'ibination of a. closed casing, a fusible elementmounted therein. and a hard deflecting shell wit-bin said casingenclosing an intermediate portion of said fusible element. said shellbeing divided transversely of said fusible element by an insulatingmember, said insulating member having a portion for preventingelectrical. communication through the material of said fusible elementafter same has been melted.

Signed at Chicago, Illinois, this 21st day of February, 1918.

ALFRED L. EUSTIGE.

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